They have a large range that extends from California all the way up to southern Canada. They are in fact the only boa in all of Canada and one of just two or three found in the U.S. The other ones in the United States are the Southern Rubber Boa (Charina umbratica) which comes from southern California and is so similar to Charina bottae that some think it's a subspecies rather than a different species, and the Rosy Boa.

The Rosy Boa gets its name from the lovely, pinkish stripes that adorn its body. The Rubber Boa gets its name from the way it looks, too...

Rubber Boas look really, really weird. They're covered in lots of tiny, shiny scales and their skin doesn't quite fit their body. It's like they went to the snake-skin shop, spotted this slick number and thought "I HAVE to have it!" The fact that it's one or two sizes too big is, apparently, a burden they just have to bear.

I could almost understand it better if it was a big, woolly jumper. Rubber Boas are at home in much colder climates than most snakes, let alone most boas, who are usually tropical species. Rubber Boas actually get uncomfortable when it gets too hot.

This must be part of the reason why Rubber Boas spend a lot of their time hidden beneath rocks and logs or stretching their (lack of) legs in underground burrows. Sometimes these burrows are old ones previously excavated by rodents and the like, but they can also dig their own because Rubber Boas love to dig. They're good at it too, which isn't surprising because they happen to belong to the Sand Boa family.

Yup! Rubber Boas are related to our favourite dweeb, the Arabian Sand Boa! They like soft, sandy soil to burrow through, aided by their shiny scales, small eyes and the fact that their head is almost exactly the same width as their body. They don't have the kind of enormous, triangular head that a lot of snakes do and which would make digging and delving that much more difficult. It's a shame they can't have the sexy, pointy cheekbones of a viper, but sacrifices must be made.

Having said that, the Rubber Boa isn't at all limited to burrowing or staying underground. They may be rather slow and sluggish, but they can still slither around all over the place and even climb and swim if they want to. Even so, they'll need to find somewhere safe to hide when predators come calling because Sand Boas are almost completely defenceless.

Like other boas, the Rubber variety is entirely non-venomous. They do in fact have teeth, but they practically never bite. If they get attacked by a predator they roll up into a ball with their head in the centre and wave their tail around. The tail is blunt enough to look much like a head and it has a kind of shield at the end, as well as glands that produce a musky odour that will hopefully dissuade any assailants.

The Rubber Boa's amazing docility, sluggish movements, lack of venom and disinclination to bite means they're sometimes used to help people get over a fear of snakes. I love the idea of ophidiophobes graduating from a snake made of rubber to handling a real snake that looks as if it's made of rubber!

While they may be almost entirely defenceless against predators and phobics, Rubber Boas are still mean, old carnivores who'll eat any mouse, lizard or whatever else that's small enough to fit into that hungry mouth of theirs. They coil their body around prey and SQUEEZE until asphyxiation occurs. It's the boa style, of course. They'll also attack rodent nests, consuming all the babies while fending off the mother with that blunt tail.

After eating all those babies, it might be time for a snooze. Possibly for several months! Rubber Boas hibernate through the winter in underground dens. Sometimes lots of them will all get together in the same den so they can indulge in a huge orgy of sleep. That is, of course, the best kind of orgy.

When they emerge in the spring, it's time to think about babies again. Not eating them, but making them. I guess all that time in the den, rubbing their loose, glistening skin against each other, was pretty exciting.

After mating, females hold the eggs within their body and give birth to live young, much like almost all other boas. Rubber Boas produce anything up to 8 youngsters, and give birth to them somewhere between August and November. It can be up to 4 years before the female will be ready to mate again, but she might live a good 30 to 50 years before she pops her (lack of) clogs so she has time to wait.

Newborns are already about 20 cm (8 in) long. That's quite impressive for one so young, but it's probably not big enough to eat a baby shrew. Certainly not big enough to fight off a mother shrew. You have to be big and strong to eat babies. Besides. it's important to have something to look forward to.